StiReport1.Load("فایل گزارش");

Stimulsoft.Report.Dialogs.StiForm frm = (Stimulsoft.Report.Dialogs.StiForm)StiReport1.Page  s(1).Components.Item("");

Stimulsoft.Report.Dialogs.StiComboBoxControl combo1 = (Stimulsoft.Report.Dialogs.StiComboBoxControl)frm.  Components.Item("ComboBoxControl1");

combo1.Items.Add("هرچی میخوای");